Rolle cutter retaining device



A ril 25, 1933. H, WELLENSIEK ET AL 1,905,079

ROLLER CUTTER RETAINING DEVICE Filed Nov. 21, 1951 WERLLEHSIEK nH a INVENTORS BY DER ATTORNEY tered into position beco ployed is ai drill having a Patented Apr. 25, 1933 PATENT OFFICE UNITED sures LOUIS n. wmmmgrm m c. sm'rn, :3... or nous'ron', mas, morons mp Evens 'roor. consu /(8' novsros, arms, a comm'nort or nus J norms cums. RETAINING nnvrcn Application led November 81, 1981. Serial Io. 876,510.

Our invention relates to wu f w roller cutters thereon and pe/ P 2 9- larly to the construction ofi e ms means by which the cutters d 111 P 5 tion upon their shafts.

Where balls interfitting Etween the F- ter and the shaft upon whch the cutter is mounted, are used to re thecutter in place the means by whichth balls are mis a problem. If an opening through the ;hell of the cutter to the ball race is provided, the cutter is weakened, and a material part of the cutting surface of the cutter isi'emoved. This is a 5 marked objection as it"interferes with the cutting act1on of the cltter and lowers the cutting capacity of earth set of cutters. If the balls are inserted through the axis of the shaft it necessitates i lateral or transverse bore from the axial opening to the raceway and increases the 06st of construction and weakens the shaft somewhat.

It is an object of ourinvention to provide a construction whereby the balls may be inserted to the raceway b way of one straight bore in the cuttergsh'a leading directly to the raceway. This invention includes a plug to fill the opening after it has served its purpose to also low the passage of the balls, which plug acts to strengthen the shaft and form part of the raceway.

We also desire to employ a separate antifriction bearing for the cutter, acting to hold the cutter spaced uniformly from the shaft and allow free circulation of fluid about the cutter bearings.

In the drawing herewith, Fig. 1 is a side view partly in centralvertical section of a well drill employing our invention.

Fig. v2 is a side elevation of the retaining pin, removed.

The tool :up'on which our invention is emhead 1 with a threaded shrink 2 and diverging legs 3 thereon. Upon eich leg is an inwardly and downwardly exte ding cutter shaft 4 formed integral there *ith'. Surrounding the end of each shaft and rotatable thereon is an approximately conical shaped cutter 5 formed with teeth 6 thereon.

These cutters are generally old in the art but their method of mountin has been changed from that formerl emp oyed. The interior of each cutter is ormed with a recess 7 shaped to fit over the end of its shaft 4 so as to allow free clearance about the shaft to allow circulation of slush or to receive lubricant. The interior wall of the cutter has two annular half round grooves 8 and 9to provide races for the balls 10 and 11 respectively. The balls 10 are retaining balls and act to retain the cutter on the shaft. The balls 11 are anti-friction bearings also acting to space the cutter from the shaft.

The shaft 4 has grooves 12 and 13 to receive the balls 10 and 11 respectively. The balls 11 are placed in the race 9 in the cutter and held in place by a heavy grease when the cutter is placed on the shaft. The balls 10 have to be inserted when the cutter is in place on the shaft.

To introduce the balls 10 a hole 14 is bored through the leg 3 of the bit head and down one side of the shaft 4, the inner end of this hole being curved slightly toward the outside and terminates at a point registering with the outer rim of the race 12 in the shaft. When the balls are dropped into this hole they pass they are all a pin 15.

in place the hole is plugged with The pin has its inner end shaped to conform to the shape of the shaft 4 and raceway 12 therein. It has a curved recess 16 to conform to the shape of the raceway and a recessed shoulder 17 to register with the outer surface of the shaft adjacent the raceway. The outer end of the pin has a transverse opening to receive a cotter-pin or rivet extending therethrough. In addition, we contemplate placing a bond of welding metal 18 about the pin to hold it rigidly in place.

The cutter, thus mounted, will rotate frees 1y on its shaft. The two ball races are arranged to space the cutter uniformly from the shaft and to allow circulation of slush or lubricant. The forward balls 11 take up the end thrust upon the shaft. The balls 10 as anti friction bearings.

The forming of the opening 14in the par-- ticular position shown so that the balls may pass through a bore hole in the bit head directly to the bearing race without the necessity of a branching passage makes the construction cheaper; 1t assures the insertion of the balls without chokin of thepassage, and enables the operator to 511 the opening with a straight pin which prevents weakening of the cutter shaft and presents a smooth race in the shaft for the balls 10. The opening 14 need not be parallel with the axis of the shaft but must be a straight bore which may be completely filled with a plug pin as shown. What we claim as new is: i 1. In a well drill, a head, cutter shafts thereon tapered adjacent their ends, said shafts having grooves thereon for ball bearings, one of which is upon said tapered area, balls in said grooves, cutters on said shafts and a bore in said head and shaft leading in a straight line to oneof said grooves, and

means to fill said bore holding the balls in said oove. H

2. n a well drill, a head, a pair of opposed inwardly inclined shafts integral with said head, cylindrical bores in said head and shafts parallel with the axes of said shafts, cutters surrounding the ends of said shafts, a row of balls interfitting in a groove between each' shaft and its cutter to retain said cutter rotatably on said shaft, said bores terminating in said grooves, and a cylindrical plug in said bore acting to prevent weakening of said shafts.

In testimony whereof, we hereunto afiix our signatures this the 18th day of November A. D. 1931.

LOUIS H. WELLENSIEK. FRED G, SMITH, JR. 

